import java.util.Scanner;
public class Test8 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        BulbSwitcher switcher = new BulbSwitcher();
        int result = switcher.bulbSwitch(n);
        System.out.println(result);
        scanner.close();
    }
}
class BulbSwitcher {
    public int bulbSwitch(int n) {
        return (int) Math.sqrt(n);
    }
}